US6863615B2 - Centered double universal joint - Google Patents

Abstract

A centered double universal joint has a first outer joint yoke (1) with first centering means (4, 6), a first inner joint yoke (8), a first cross member (10) connecting the first outer joint yoke (1) via rolling bearings (11) to the first inner joint yoke (8), and a first lubricant channel (44) for lubricating the rolling bearing (11). Also, the joint has a second outer joint yoke (12) with second centering mechanism (15, 17), a second inner joint yoke (19), and a second cross member (21) connecting the second outer joint yoke via rolling bearings (22) to the second inner joint yoke (19). A guiding disc (25) has a first central centering projection (28) articulatably connected to the first centering means (4,6). The guiding disc has a second central centering projection (29) articulatably connected to the second centering means (15, 17). Guiding faces (32, 33) on the guiding disc (25) are radially adjustably guided in an annular recess (24) of a housing (9, 20). The first lubricating channel (44) is connected to a first lubricant guiding mechanism (50) of the first centering mechanism (4, 6). The guiding disc (25) has a lubricant channel (51, 53) which is connected to the first lubricant guiding mechanism (50) and ends in at least one of the guiding faces (32, 33).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application No. 10135347.2 filed Jul. 20, 2001, which application is hereby expressly incorporated by reference.

FIELD OF THE INVENTION

The invention relates to a centered double universal joint, especially for driving, or for drives in, agricultural implements and tractors.

BACKGROUND OF THE INVENTION

DE 39 21 242 C1 (which is the priority document for U.S. Pat. No. 4,997,407) describes a centered double universal joint with two outer joint yokes articulatably connected by a cross member to two inner joint yokes to form part of a housing. An annular recess is formed in the housing. A guiding disc is radially adjustably supported in the housing. Floating annular guiding plates sandwich the guiding disk. The guiding disc includes a centrally arranged guiding projection. The projection projects from both sides of the guiding disc. The outer joint yokes, whose yoke arms are connected to one another by a bridge, each include a journal projection. The journal projection includes a spherical face and is pivotably supported in a bore of the central guiding projection of the guiding disc. The cross members each include lubricating channels which are used to lubricate rolling contact bearings. The rolling contact bearings support the cross member in the yoke arms. The lubricating channels are each connected to lubricant guiding means in the journal projections. The channels open into the bore of the central guiding projection of the guiding disc. At least one radially extending lubricant channel is provided in the guiding disc. The channel connects the bore in the central guiding projection to the annular recess. It is thus possible to convey lubricant from a lubricating nipple, provided at the cross member, into the annular recess. The disadvantage, however, is that at high rotational speeds of the double universal joint, the lubricant is thrown radially outwardly as a result of the centrifugal forces. This has an adverse effect on the lubrication of the guiding disc and the guiding plates.

DE 28 02 572 C2 (which is the priority document for U.S. Pat. No. 4,257,243) discloses a centered double universal joint wherein a guiding disc, articulatably connected via centering projections to outer joint yokes, is radially adjustably guided in an annular recess. The housing includes a lubricating nipple which is directly connected to the annular recess by a lubricant channel. Thus, the rolling contact bearings of the cross members and the annular recesses are lubricated independently of one another. Accordingly, the lubricant is pressed radially outwardly by the centrifugal forces.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a centered double universal joint with a guiding disc that improves the lubrication of the guiding disc.

In accordance with the invention, a centered double universal joint includes a first outer joint yoke with first outer yoke arms. A first bridge connects the first outer yoke arms to one another. A first centering mechanism is associated with the first bridge. A first inner joint yoke includes first inner yoke arms. A first cross member articulatably connects the first outer yoke arms, via rolling contact bearings, to the first inner yoke arms. The first cross members has first lubricant channel for lubricating the rolling contact bearings. A second outer joint yoke has second outer yoke arms. A second bridge connects the second outer yoke arms to one another. A second centering mechanism is associated with the second bridge. A second inner joint yoke includes second inner yoke arms. A second cross member articulatably connects the second outer yoke arms, via rolling contact bearings, to the second inner yoke arms.

A guiding disc defines a longitudinal axis. The guiding disc has a first central centering projection articulatably connected to the first centering mechanism of the first outer joint yoke. The guiding disc has a second central centering projection articulatably connected to the second centering mechanism of the second outer joint yoke. Guiding faces on the guiding disc radially adjustably guided the guiding disc in an annular recess of a housing. The first inner joint yoke and the second inner joint yoke form part of the housing. The first lubricating channel of the first cross member is connected to first lubricant guiding mechanism of the first centering mechanism. The guiding disc has at least one lubricant channel connected to the first lubricant guiding mechanism of the first centering mechanism. The lubricant channel ends in at least one of the guiding faces.

An advantage of this design is that the lubricant channel of the guiding disc ends directly in a guiding face. Thus, this ensures that the guiding face is directly lubricated.

When the guiding disc is directly supported in the annular recess of the housing, the guiding faces of the guiding disc are in sliding contact with the annular sealing faces which delimit the annular recess. The lubricant passes through the lubricating channel of the guiding disc and enters the region directly between the guiding face of the guiding disc and the sealing face of the annular recess. When annular guiding plates are provided between the guiding faces of the guiding disc and the sealing faces of the radial recess, lubricant is directly introduced between the guiding face of the guiding disc and a sealing face of the guiding plate.

Furthermore, it is possible to provide a common lubricant connection between the cross member and the guiding disc. This is accomplished by the connection of the first lubricant channel of the first cross member and the lubricant channel of the guiding disc, via the first lubricant guiding means of the first centering means. This means that when the first cross member is lubricated, the first centering means and the guiding disc are lubricated at the same time.

To achieve an easy-to-produce embodiment, the guiding disk lubricant channel includes a first bore extending radially relative to the longitudinal axis. The first bore is open to the annular guiding recess. A second bore extends parallel to the longitudinal axis and ends in at least one of the guiding faces.

An easy connection between the first lubricant channel of the first cross member and the first lubricant guiding mechanism of the first centering mechanism can be ensured by the first lubricant channel of the first cross member. The first lubricant channel of the cross member includes a bore opening towards the first bridge. The bore is connected to the first lubricant guiding mechanism of the first centering mechanism by a resilient hose.

Accurate control of the two universal joints and a long service life are achieved by providing the guiding disc with a cylindrical bearing bore. The bearing bore extends through the first centering projection and the second centering projection. The bore extends coaxially relative to the longitudinal axis. The first centering mechanism and the second centering mechanism each include a bearing journal which extends coaxially relative to an axis of rotation of the respective outer joint yoke. A bearing ball is provided in each bearing journal. The bearing ball is in the form of a spherical layer with a spherical outer face. A through-bore in the bearing ball positions the bearing ball on the bearing journal. The bearing ball is held at least axially relative to the axis of rotation. A bearing race pivotably supports the bearing ball on the outer face of the bearing ball. A corresponding hollow-spherical bore in the bearing race receives the bearing ball. The bearing race has a cylindrical outer face for axially adjustably positioning the bearing race in the cylindrical bearing bore of the guiding disc.

According to a preferred embodiment, annular guiding plates are provided on both sides of the guiding disc in the annular recess. The annular recess is closed on the radial outside. The outer diameter of the guiding plates is greater than the inner diameter of the annular recess and smaller than the greatest diameter of the annular recess. The inner diameter of the guiding plate is greater than the outer diameter of the centering projections of the guiding disc and smaller than the outer diameter of the guiding disc. The at least one lubricant channel of the guiding disc opens towards at least one guiding plate.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

The FIGURE is a side view of an inventive double universal joint, partially in section. The double universal joint includes two individual universal joints which are connected to one another via a centering mechanism. Both joints each accommodate half the angle of articulation when an input shaft is articulated relative to an output shaft in order to ensure constant velocity. The two individual joints are substantially identical in design.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

The double universal joint includes a first outerjoint yoke1 with two firstouter yoke arms2. The free ends of the yoke arms are connected to one another by a first bridge3. The first bridge3 carries a first bearing journal4 defining afirst axis5. The outer face of the first bearing journal4 is cylindrical. A first bearing ball6, in the form of a spherical layer, is immovably held on the first bearing journal4 along thefirst axis5. The spherical outer face of the first bearing ball is identified by reference number7. The first outerjoint yoke1 is articulatably connected to the first innerjoint yoke8 via afirst cross member10 and a rollingbearing11. The first innerjoint yoke8, with its two yoke arms, is produced to be integral with a first bearing housing9.

The second joint includes a second outerjoint yoke12 with twoouter yoke arms13. Again, only one yoke arm is visible. The twosecond yoke arms13 are connected to one another by a second bridge14. The second bridge carries asecond bearing journal15. The second bearing journal has a cylindrical outer face and is centered on thesecond axis16. A second bearing ball17 is immovably and axially held on thesecond bearing journal15 along thesecond axis16. The bearing ball17 has a sphericalouter face18. The second outerjoint yoke12 is articulatably connected to theyoke arms13 of the second innerjoint yoke19 via asecond cross member21 and rolling bearings. The second innerjoint yoke19 is also produced to be integral with a secondbearing housing portion20.

The first bearing housing portion9 and the secondbearing housing portion20 are removably connected to one another bybolts23. The twohousing portions9,20, together, form a radially outwardly closed and radially inwardly openannular recess24. A guidingdisc25 and guidingplates26,27 are radially adjustably accommodated in therecess24. Thefirst guiding plate26 and thesecond guiding plate27 are arranged on either side of the guidingdisc25. The diameters of the twoannular guiding plates26,27 of the guidingdisc25 and of theannular recess24 are adjusted to one another such that the articulation-related adjustment of the guidingdisc25 in theannular recess24 can be carried out. However, the guidingdisc25 is held securely in the recess. Accordingly, the greatest diameter of theannular recess24 is greater than the outer diameter of the twoannular guiding plates26,27 and greater than the outer diameter of the guidingdisc25. However, the inner diameter of the twoannular guiding plates26,27 is smaller than the outer diameter of the guidingdisc25.

The guidingdisc25 includes a central first centeringprojection28 and a second centeringprojection29. A cylindrical bearing bore30 defining alongitudinal axis31 extends through theprojection28,29. The first centeringprojection28 projects beyond a first guidingface32 of the guidingdisc25. The second centeringprojection29 projects beyond asecond guiding face33 of the guidingdisc25. This is the reason why the smallest diameter of theannular recess24 is greater than the outer diameter of the guidingprojections28,29. Furthermore and accordingly, the inner diameter of theannular guiding plates26,27 also has to be greater than the outer diameter of the guidingprojections28,29.

A first bearing race34 is positioned on the first bearing ball6. A hollow-spherical bore of the first bearing race34 is adapted to receive the spherical outer face7 of the first bearing ball6. The first bearing race34 has a cylindrical outside surface which is displaceably guided in the bearing bore30. Accordingly, the second bearing ball17, via its sphericalouter face18, is received in a corresponding hollow-spherical bore of asecond bearing race35. Thesecond bearing race35 is also received in the bearing bore30 by its cylindrical outer face.

The twocross members10,21 each include fourtrunnions36. Two trunnions are always arranged on acommon trunnion axis37,38. Thetrunnions36 are supported inbores39 of theyoke arms2,13,40,41 by rollingcontact bearings11,22. The rollingcontact bearings11,22 each include a bearingbush42 arranged in therespective bore39. Also, rollingmembers43 roll on the outer face of therespective trunnion36 and on an inner face of therespective bearing bush42.

For the purpose of lubricating the rolling contact bearing11, thefirst cross member10 includes afirst lubricant channel44. Thefirst lubricating channel44 includes abore45 which extends along thetrunnion axis37 of twotrunnions36. Furthermore, thefirst lubricant channel44 includes abore46 which extends along theother trunnion axis38. Thebores45,46 start from the end face of atrunnion36 and end in an end face of theremote trunnion36. Thebores45,46 intersect one another in the center of thecross member10. One of thetrunnions36 includes a lubricatingnipple47 which is connected to thefirst lubricant channel44. Via this route, thefirst lubricant channel44 can be supplied with lubricant.

Thefirst cross member10 includes a further bore48 which leads to thefirst lubricant channel44. The bore48 is in a plane that extends perpendicular to the plane extending through the twotrunnion axes37,38. A flexible hose49 is inserted into the bore48. The flexible hose49 leads to the firstlubricant guiding mechanism50. The first lubricant guide mechanism is a through-bore in the first bearing journal4. The other end of the hose49 is inserted into thelubricant guiding mechanism50. The firstlubricant guiding mechanism50 ends in the bearing bore30.

Lubricant channels51 are provided in theguiding disc25. Thelubricant channels51 are in the form of radial bores that lead from the bearing bore30 to theannular recess24. Through-bores53 are provided near an outercircumferential face52 of the guidingdisc25. The outercircumferential face52 is delimited by the guiding faces32,33. Through-bores53 form a further part of thelubricant channel51 and extend axis-parallel to thelongitudinal axis31. The through-bores53 intersect a radial bore of therespective lubricant channel51. Thus, each through-bore53 leads from the first guidingface32 to the second guidingface33. This means that the guiding faces32,33 are directly lubricated with lubricant between the guiding faces32,33 and the respective surface of the guidingplates26,27. The through-bore53 is arranged on a diameter around the longitudinal axis. The diameter ensures that the through-bores53 are closed in each angular position of the two joints by the guidingplates26,27.

Thesecond cross member21 is identical to thefirst cross member10 and include the same reference numbers. However, there is no connection between thesecond lubricant channel44′ and the bearing bore30.

It is also possible for the guiding disc to be supported in an annular recess without being sandwiched between guiding plates. The lubricant, in such a case, is guided through the through-bores into the region between the sealing faces and the sliding faces of the annular recess.

While the above detailed description describes the preferred embodiment of the present invention, the invention is susceptible to modification, variation and alteration without deviating from the scope and fair meaning of the subjoined claims.

Claims (5)

1. A centered double universal joint comprising:

a first outer joint yoke with first outer yoke arms;

a first bridge connecting the first outer yoke arms to one another;

a first centering mechanism associated with the first bridge;

a first inner joint yoke including first inner yoke arms;

a first cross member articulatably connecting the first outer yoke arms via rolling contact bearings to the first inner yoke arms;

a first lubricant channel for lubricating the rolling contact bearings provided in the first cross member;

a second outer joint yoke with second outer yoke arms;

a second bridge connecting the second outer yoke arms to one another;

a second centering mechanism associated with the second bridge;

a second inner joint yoke including second inner yoke arms;

a second cross member articulatably connecting the second outer yoke arms via rolling contact bearings to the second inner yoke arms;

a guiding disc defining a longitudinal axis, said guiding disc having a first central centering projection articulatably connected to the first centering mechanism of the first outer joint yoke, said guiding disc having a second central centering projection articulatably connected to the second centering mechanism of the second outer joint yoke, and guiding faces on the guiding disc being radially adjustably guided in an annular recess of a housing, the first inner joint yoke and the second inner joint yoke forming part of the housing;

the first lubricating channel of the first cross member being connected to first lubricant guiding mechanism of the first centering mechanism; and

the guiding disc having at least one lubricant channel which is connected to the first lubricant guiding mechanism of the first centering mechanism, said at least one lubricant channel extend to a circumferential surface of said guiding disc and ending in at least one of the guiding faces.

2. A centered double universal joint according toclaim 1, wherein the lubricant channel of the guiding disc includes a first bore extending radially relative to the longitudinal axis and open to the annular guiding recess, as well as a second bore extending parallel to the longitudinal axis and ending in at least one of the guiding faces.

3. A centered double universal joint according toclaim 1, wherein the first lubricant channel of the first cross member includes a bore opening towards the first bridge and connected to the first lubricant guiding mechanism of the first centering mechanism by a resilient hose.

4. A centered double universal joint according toclaim 1, wherein a cylindrical bearing bore is provided in the guiding disc extending coaxially relative to the longitudinal axis through the first centering projection and the second centering projection, said first centering mechanism and the second centering mechanism each comprise a bearing journal extending coaxially relative to an axis of rotation of the respective outer joint yoke; and

a bearing ball is provided per bearing journal in the form of a spherical layer with a spherical outer face, a through-bore in said bearing ball for positioning said bearing ball on the bearing journal and said bearing ball being held at least axially relative to the axis of rotation; and

a bearing race is provided per bearing ball pivotably supporting the outer face of the bearing ball in a corresponding hollow-spherical bore in said bearing race and a cylindrical outer face on said bearing race for axially adjustably positioning said bearing race in the cylindrical bearing bore of the guiding disc.

5. A centered double universal joint according toclaim 1, wherein annular guiding plates are arranged on both sides of the guiding disc in the annular recess, the annular recess being closed on its radial outside, the outer diameter of the guiding plates being greater than the inner diameter of the annular recess and smaller than the greatest diameter of the annular recess, the inner diameter of the guiding plate being greater than the outer diameter of the centering projections of the guiding disc and smaller than the outer diameter of the guiding disc, and the at least one lubricant channel of the guiding disc opens towards at least one guiding plate.

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